The application of the invention is the lifting of wheel-mounted vehicles, for example in particular but not solely automobiles.
Typically, the handling consists of moving a vehicle inside or near to a garage, a workshop (for bodywork, mechanical work, etc.), a showroom, a car park, etc. In general, it is not possible to move the vehicle on its own wheels, because it is has been damaged or it has broken down, or because it is locked with the handbrake or the steering lock on (or in gear).
More precisely, the invention concerns a lifting trolley of the type, which permits at least a wheel of a vehicle to be lifted and supported.
In the following description, the example used is that of an automobile that is to be moved. It is obvious, however, that this invention can be used for all types of vehicles to be moved, provided that it is wheel-mounted.
It is known that to move an automobile, one or more lifting trolleys are to be used. In general, a trolley is placed under each of the two front (or rear) wheels, so that the automobile can be pivoted effortlessly around its rear (or front) axle. Trolleys may even be placed under each of the four wheels, so that the automobile may be turned around completely (again effortlessly), without the assistance of a breakdown truck.
It is known, in the state of the technology, of a lifting trolley structure, composed of two support assemblies, mounted on castors, and mechanisms for moving the two support assemblies in relation to one another. Each of the support assemblies has a telescopic part, which works with the telescopic part of the other support assembly, and a transversal part fixed (in general, more or less perpendicularly) to a free end of the telescopic part, and which supports at least one castor. A trolley with such a structure can adopt in particular a rest position and a raised position. In the rest position, the two telescopic parts are moved apart from one another, so that the trolley may be placed under the wheel to be lifted, with the rollers positioned on either side of the wheel. In the raised position, the two telescopic parts are moved towards one another, so that the wheel is lifted and supported by the rollers.
A first known lifting trolley, which has the previously mentioned structure, is described in the French patent request no FR 97 14877, registered in the name of Mr. TORTELLIER. In particular, we refer to FIG. 15 of this patent request. In this case, each transversal part has a main body which has a fold which defines a flat portion and an angled portion. The main body is attached, by one end of its flat portion, to the free end of one of the telescopic parts. A pivoting castor is mounted under each of the two ends of the flat portion. Two support brackets are attached to the two ends of the angled portion, to support a spindle (more or less perpendicular to the telescopic parts) on which a roller is mounted and rotates around. Furthermore, the mechanism for moving the two support assemblies with respect to one another, includes a ratchet tensioner that adjusts one strap, one end of which is attached to a support element (or spindle) which in turn is directly attached to one of the telescopic parts.
A second known lifting trolley, which has the previously mentioned structure, is described in the European patent request no EP 317 044, registered in the name of Mr. COCCARO. In particular, we refer to FIG. 2 of this patent request. In this case, each transversal part has a straight central section with two ends, from each of which runs a section with a stepped end. A pivoting castor is mounted under each stepped end section. The straight central section, as the stepped end sections, are pieces of flat iron. The first (called the first) of the stepped end sections is welded on top of the free end of one of the two telescopic parts. The other (called the second) stepped end section is attached onto one of the ends of the straight central section, by means of a removable coupling. A roller is mounted so that it rotates around the straight central section, by means of two bearing bushes fixed onto the two ends of this straight central section. Furthermore, the mechanism for moving the support assemblies with respect to one another has dual direction gear rack, which is pedal operated.
A variation of the second known trolley is also known, in which a same piece of flat iron forms the straight central section and the second end section. Therefore, no coupling is used.
It appears that neither of the two known trolleys described previously offers a satisfactory solution for the transversal parts, in particular as concerns mounting rollers onto them. It should be remembered that they are mounted both during the initial assembly of the trolley and also each time that the used rollers are changed.
The transversal parts of the first known trolley are relatively complex, and consequently are quite difficult to manufacture and mount. It should be remembered that each transversal part has a main body (with a flat and an angled portion) as well as two brackets which support a spindle on which the roller is mounted and rotates.
The transversal parts of the second known trolley are simpler. In fact, the rollers are mounted so that they rotate directly around the straight central sections. However, with these transversal parts, it is difficult to mount the rollers, as this requires one of the two stepped end sections to be removed first (which is to say the one not welded onto one of the telescopic parts). It should be remembered that the stepped end section to be removed is fixed via a removable attachment to one end of the straight central section, by means of a coupling.
It can be noted that in the case of the previously mentioned variation of the second known trolley, it is also difficult to mount the rollers as to do so it is necessary to remove the castor supported by the second end section. This is in fact obligatory in order to remove the roller by sliding it along the flat iron.
The way in which the rollers are mounted also means that it is necessary to fit two bearing bushes onto each end of each straight central section.
In addition, the rotation of each roller on two bearing bushes causes rapid wear of the internal wall of the roller, and especially the bushes, which means that these parts are changed more often.
Furthermore, the fact that one of the stepped end sections is welded to the top of the free end of one the two telescopic parts means that it is consequently close to the ground when used. The roller on the transversal part in question should also be as close to the ground as possible, but if the telescopic parts are too close to the ground, this can be a problem.
Finally, in the first and second known trolleys, the transversal parts are welded onto the telescopic parts. The trolley therefore is U shaped in general, which means that it is not easy to store or to transport.
The invention aims in particular to overcome these different disadvantages of the state of the technology.
More precisely, one of the objectives of this invention is to provide such a lifting trolley, which has the previously mentioned structure, but which does not have the disadvantages of the transversal parts of the first and second known trolleys described above.
Another objective of the invention is to provide such a lifting trolley whose transversal parts are relatively simple, easy to manufacture and mount and inexpensive.
Another objective of the invention is to provide such a lifting trolley whose rollers can be easily removed and mounted.
Another objective of the invention is to provide such a lifting trolley whose transversal parts have good resistance to loads.
Yet another objective of the invention is to provide such a lifting trolley which can be stored and transported compactly.
An additional objective of the invention is to provide such a lifting trolley which limits the wear of the rollers.
These various objectives, as well as others which will subsequently become apparent, are achieved in the invention with the use of a lifting trolley, the type which permits at least a wheel of a vehicle to be lifted, the said trolley comprising two support assemblies, mounted on castors, and means for moving the two support assemblies with respect to one another, the said trolley being able to be placed in a rest position and in a raised position, each of the said support assemblies including a telescopic part working with the telescopic part of the other support assembly, and a transversal part fixed (in general, more or less perpendicularly) to a free end of the said telescopic part, and supporting at least one castor. According to this invention, each of the said transversal parts has a straight central section with a first free end and a second end from which runs a section with a stepped end, with at least one pivoting castor being mounted and rotating on the said straight central section. Moreover, each of the said transversal parts is attached to the free end of one of the telescopic parts by the said first free end of the said straight central section. At least one castor is mounted under the free end of each of the telescopic parts.
The general principle of the invention therefore consists of simplifying the structure of the transversal parts (rollers mounted directly on the straight central sections but with a single stepped end section for each transversal part) and attaching certain rollers directly to the telescopic parts.
Advantageously, for each of the said transversal parts, the said stepped end section is attached by means of a fixed attachment to the second end of the said straight central section.
Therefore, the structure of the transversal part does not have any coupling (contrary to the second known trolley).
Advantageously, each of the said transversal parts is attached by means of a fixed attachment to the free end of one of the telescopic parts, by the first end of the said straight central section.
In this way, mounting and removing the rollers is simple and rapid. Moreover, the trolley according to the invention may be stored and transported easily and compactly (transversal parts removed and, for example, positioned parallel to the telescopic parts).
In preference, the said removable attachments will have a sheath and associated locking device. The sheaths have the advantage of good load resistance, while remaining simple in terms of their design and application (in particular when mounting/removing rollers).
In preference, the said removable attachments will be located under the free end of one of the telescopic parts. Therefore when operating, the telescopic parts of the trolley according to the invention can be moved further away from the ground than those of the second known trolley. The rollers of the trolley according to the invention remain however as close to the ground as those of the second known trolley.
In preference, the said straight central section of each of the said transversal parts is a section of bar which is more or less cylindrical. In this way, bearing bushes are not required and the wear of the inside wall of the rollers is also limited (thanks to the rotation on a suitably shaped spindle).
In one particular embodiment of the invention, the said mechanism for moving the two support assemblies with respect to one another includes a lifting strap and a device to actuate the said strap so as move the trolley from the rest position to the raised position. The said device for actuating the lifting strap is attached to one of the said telescopic parts. The first end of the said lifting strap is attached to the said device for actuating the lifting strap, and the second end is attached to an end support, which is attached to one of the said transversal parts.
In other words, the end support is not attached directly to one of the telescopic parts, but is attached to one of the transversal parts. This therefore creates a synergy with the general concept of the invention, which provides that one of the ends of the transversal parts has no stepped end section, and therefore does not support a castor.
According to a first advantageous variation, the said end support is attached to that of the said transversal parts which is not attached to the telescopic part upon which the lifting strap actuating device is attached.
Consequently, this means that the strap is directly tensioned. This first variation applies in particular to the production of a trolley for lifting a limited load rapidly.
According to a second advantageous variation, the said end support is fixed to that of the said transversal parts which is attached to the telescopic part upon which the lifting strap actuating device is attached. Moreover, the said strap has a pulley system which passes via an intermediate support, fixed to the said transversal part which is not attached to the telescopic part upon which the lifting strap actuating device is attached.
The strap is consequently tensioned indirectly in this case, which means that the load is halved. This second variation applies in particular to the production of a trolley for lifting a heavier load more slowly.
In preference, the said end support and/or the said intermediate support are part of a unit comprising:
the free end of the straight central section of one of the said transversal parts;
a support, attached at least to a bracket which is part of the attachment of one of the said transversal parts and to the free end of one of the said telescopic parts.
It is clear that the intermediate support is only present in the second variation (pulley system). It can also be noted that in the case of the second variation, the end support and the intermediate support (each situated in one of the two support assemblies) are not necessarily of the same type. In other words, one may be a free end of a straight central section, while the other may be a support.
In preference, the said lifting strap actuating device include a ratchet tensioner. It is important to note that the ratchet tensioner is not only used to tension the lifting strap, but also to lift the wheel.